Communication devices have been miniaturized due to the development of electrical electronic technology. Also, the mobility of communication devices has become excellent due the rapid development of mobile communication technology. Due thereto, modern people are able to conveniently carry portable terminals which provide various communication services.
Portable terminals described above may be classified depending on coupling between a body and a display and an opening/closing type into folder type portable terminals, flip type portable terminals, slide type portable terminals, swing type portable terminals, complex type portable terminals, and bar type portable terminals.
As generations of electrical electronic technology and mobile communication technology have been developed, portable terminals perform various additional functions as a so-called computer in hand more than an original use thereof such as communication at a long distance. That is, a high-definition digital camera is attached to add a camera function, and a high-capacity memory is mounted to play MP3, various games, and movies due to the development of memory technology. In addition, a generation of multi-functional cellular phones with global positioning system (GPS), online communication, etc., which are so-called smart phones, has been open.
Smart phones recently released exclude a keyboard with a plurality of buttons essentially provided on a body of a general portable terminal due to touch-screen technology and bar type portable terminals among various types of portable terminals described above become mainstream. This is because a large display panel is necessary instead of an additional keyboard and a large number of functions are added to increase a size of a main board on which a central processing unit (CPU) and various chips are mounted.
Also, as sizes of a display panel and a main board which form a mobile communication terminal increases, to discharge heat generated inside the mobile communication terminal, a bracket frame having a flat panel structure which supports the display panel and main board inside the mobile communication terminal is formed of a metal material such as a zinc alloy, an aluminum alloy, and a magnesium alloy. To provide an exclusive feeling of an external shape, a technology for applying various colors to housing frame which forms an edge exposed outside the mobile communication terminal and protects internal components from an external shock has been attempted.
To provide a color of a surface of the housing frame, typical mobile communication terminals use a method of insertion-injecting plastic into a periphery of the bracket frame formed of the metal material to form the housing frame and performing a surface treatment process on the housing frame through vapor deposition.
However, when a housing frame exposed outside a mobile communication terminal is formed of plastic like general housing frames, not only it is difficult to maintain strength for protecting internal components but also the efficiency of releasing heat generated inside to the outside is deteriorated more than a metal material forming a bracket frame.
Also, to overcome such limitations, when a housing frame is formed of the same metal material as a bracket frame and is assembled with the bracket frame using coupling means such as screws, the numbers of manufacturing processes and components increase, thereby increasing manufacturing costs.
However, FIG. 1 is a schematic diagram of a metal frame of a smart phone formed through general extrusion and a general computer numerical control (CNC) process.
In the case of a method of manufacturing the metal frame through the general extrusion and CNC process, since it is necessary to repetitively perform the CNC process on a metal material 3 having a block structure formed through the extrusion to form a metal frame 10 of a smart phone including a housing frame 1 and a bracket frame 2 shown in the drawing, manufacturing costs greatly increase due to an increase of the CNC process.
Also, when a metal frame of a mobile communication terminal is entirely formed using a die casting process to overcome such limitations, a lot of blow holes are formed on a surface of a housing frame. Even when an anodizing treatment for forming an anticorrosive oxide film is performed, it is difficult to provide colors having a feeling of high quality material which is preferred by consumers. Accordingly, since merely simple painting using paints and varnishes is possible, it is impossible to perform surface treatment to provide the feeling of high quality material.
Accordingly, there is needed a practical and applicable technology related to a metal frame of a mobile communication terminal in which a housing frame included in the metal frame of the mobile communication terminal may be formed using a metal material to effectively release heat generated inside a mobile communication terminal, a CNC process is minimized to reduce manufacturing costs, a method of providing colors for a surface of an edge of the metal frame through anodizing is applicable.